Fig. 5

(A) Optogenetic stimulation of single neurons paired with behavioural tracking. (B) A single KalTA4u508 neuron in a 7 dpf KalTA4u508;elavl3:H2B-GcaMP6s larva that was injected at the one-cell stage with UAS:CoChR-tdTomato DNA. This ‘contra-projecting’ neuron is ‘Cell 3’ in Figure 3H. A, anterior; L, left; P, posterior; R, right. Scale bar, 100 µm. (C) Example frames from an optogenetically induced hunting event. Labels indicate time relative to saccadic eye convergence/hunting initiation. (D) Tail angle (grey) and ocular vergence angle (red) during an optogenetically induced hunting event (‘ipsi-projecting’ cell located in the left AF7-pretectum; this neuron is ‘Cell 4’ in Figure 3F; see also Video 2). Asterisk indicates time of convergent saccade. (E) Larval location colour-coded by vergence angle during the example hunting event in (D). (F) Hunting response probability for LED-On versus non-stimulation trials for larvae that performed at least one eye convergence during optogenetic stimulation (N = 23 fish). (G) Morphological identity of KalTA4u508 neurons that elicited hunting upon optogenetic stimulation. Numbers of responsive larvae are reported at the bottom (N = 23 fish). (H) Hunting response probability upon optogenetic stimulation of ipsi-projecting (orange, N = 9 cells) and contra-projecting neurons (magenta, N = 14). (I–P) Comparison of behavioural kinematics between optogenetically induced hunting events (blue, N = 23 fish) and Paramecia hunting (dark grey, N = 31). Tail kinematics for non-hunting swim bouts were recorded from the same larvae that were monitored during Paramecia hunting (light grey). In (L–P), data from all bouts are plotted, whereas in (I–K) the median or mean for each larva is reported. (Q–S) Behavioural kinematics of hunting events induced by stimulation of ipsi-projecting KalTA4u508 neurons (orange, N = 9 cells) or contra-projecting neurons (magenta, N = 14). (T) VMVs and cluster identities of KalTA4u508 neurons that induced hunting upon optogenetic stimulation and subsequently underwent calcium imaging (N = 6 cells from six fish). Symbols on the left indicate projection cell class and left/right location. HIx scores are shown on right. See also Figure 5—figure supplements 1,2 and Video 2.